Why would the vaccuum seal stop working and it stopped freezing but it still has cold air blowing

TO MANY REASONS FOR IT TO QUITE WORKING IT WOULD BE BEST TO LET SOMEONE LOOK AT IT

Do you smell coolant inside of the vehicle. If so then chances are your heater core is going.

The very first thing you need to do is to check for fuses or say faulty fuse. Secondly check fan which starts along with air conditioner, it might be manually switched off or the fan may have been clogged. Also reason can be lack of refrigerant - charge your air conditioner with refrigerant. Last thing you need to check is cooling coil - the cooling coil may freeze if there is no refrigerant in the system.

your heater core is possibly stopped up if there has been a radiator leak and stop leak has been poured its definetly clogged or could be a faulty thermostat

you have moisture in the system this causes your expancion valve to freeze up an stop working, thats why it works for sort time and when it de-freezes stars working again. you need to do a EVAC & RECHARGE with a good AC service equipment, specially attention to pull vacumm por at least 20minutes so you get all moisture out of the system.
Good luck

your cabin air filter is probably clogged up, that can cause the ac to actually freeze up and wont feel cold until the car stops and thaws out. replace your cabin filter and see if it doesnt help. ehow.com has a good step by step for the process.

you could try flushing the cooling system. this could result in a cleaner heater core, which might help the problem. good luck!

your ac compressor is freezing up try not putting it on cold all the way. put thermostat towards the red jus a lil but still on the cold side to see if that helps

The system may need to be recharged, All A/C system will have small leaks though the seals and when you lose enough R134 the system will stop blowing cold air. I am guessing that it stop working now as to that there is no cold air but the blower fan is still working right?? Or do you mean that there is cold air and then it stops making cold air after 50 miles but will work again after a few hours of the can not running. If that's the case, the A/C relay may be bad and when it heats up the relay fails and needs to be replaced. Good luck and keep me posted.

the clutch is most likely going out.